What is a prostate cancer biomarker exactly? Dr. Himisha Beltran defines biomarkers and breaks down three types of biomarkers that help guide optimal care for prostate cancer patients.
Dr. Himisha Beltran is Director of Translational Research in the Department of Medical Oncology at Dana-Farber Cancer Institute. Learn more about Dr. Beltran, here.
So, the word, ‘biomarker’ is a term that we often use that refers to a set of information or a test that provides insights into a particular diseased state. And in prostate cancer, there are several different types of biomarkers that we use. There are diagnostic, prognostic, and predictive biomarkers. And each of them provide different sets of information. A diagnostic biomarker is a test that improves the diagnosis of prostate cancer, and one that we are very familiar with is PSA test. This is a test that’s commonly done that may lead a suspicion of cancer. That leads to an additional work-up for prostate cancer. And there are other tests, urine, blood, and tissue-based, that can improve the detection of prostate cancer as well as specific types of prostate cancer.
Then there are prognostic biomarkers. A prognostic biomarker is a biomarker that provides insight into how indolent or aggressive a cancer is. And this can inform treatment decisions for newly diagnosed patients in trying to consider whether you should do active surveillance or get local therapy. In the more advanced disease setting, a prognostic biomarker can help us think about treatment intensification strategies for patients that are predicted to not respond as well to traditional approaches. And these are often molecular tests.
And then there are predictive biomarkers, which in opinion, are quite informative in trying to make a prediction as to how likely will respond to a specific treatment. And this is a really emerging field. And in an advanced prostate cancer, one example of a predictive biomarker is a mutation in a gene called BRCA2, which can identify patients more likely to respond to a PARP inhibitor versus those that do not. That’s just one example of how we may be able to use molecular features of a cancer to provide insights into what therapy that patient might benefit from most.
There are no perfect biomarkers. All of these types of biomarkers are just tools that we use to help guide treatment decisions at different stages of prostate cancer.